LeDoux Lab 2017 SfN Abstracts
 
Program#/Poster#: 417.16 / RR14
Title: Mediated generalization in active avoidance
Location: Halls A-C
Presentation Time: November 13, 2017, 1:00 - 5:00 PM
Presenter at Poster Mon, Nov. 13, 2017, 4:00 PM - 5:00 PM
Authors: *V. CAMPESE11, T. J. MARTIN1, C. H. ROBERTS1, C. DRAUS1, J. E. LEDOUX1,2;
1Ctr. for Neural Sci., New York Univ., New York, NY; 2Emotional Brain Inst., Nathan Kline Inst., Orangeburg, NY
Abstract: In Pavlovian to instrumental transfer (PIT) a conditioned stimulus (CS) that has been paired with an unconditioned stimulus (US) energizes goal directed behavior. PIT has typically been studied using appetitive reinforcement, and has provided an effective model that has advanced our understanding of the psychobiological substrates of appetitive motivation. However, we still know relatively little about aversive motivation. Aversive versions of PIT typically employ unsignaled active avoidance behavior and demonstrate control over this class of responding by a CS for an aversive US (e.g., shock). The psychological and neural mechanisms underlying aversive PIT are not well understood but early findings indicate it is a unique form of avoidance behavior. In order to further explore aversive PIT we evaluated whether generalization known as acquired equivalence is involved in transfer. In this framework, stimuli that predict the same US come to be treated as similar, increasing generalization between them. To explore if context-shock and tone-shock pairings contribute to this, subjects were exposed to two avoidance chambers during training. In context A (a standard avoidance chamber) shuttling was acquired as a footshock avoidance response using an unsignaled Sidman procedure, whereas in context B (another avoidance chamber with checkered walls and smooth floors), shock was never delivered. A shock-paired CS produced less transfer (i.e., PIT) in context B than in context A. This suggests that at least in part, the aversive PIT effect is driven by the avoidance context and may be due to generalization via shock. We followed this by testing if PIT requires regions of the brain that have been implicated in spatial learning (e.g., hippocampus) and mediated generalization (e.g., entorhinal cortex). Designer hM4Di receptors were used to inhibit these regions during PIT testing, but found no behavioral effect. Subjects then underwent training on a negative patterning task, which studies have found involve both hippocampal and entorhinal regions. Inhibition of these regions via treatment with CNO (the ligand for designer receptors) impaired acquisition of the negative patterning discrimination relative to vehicle controls and a non-viral CNO control group. This pattern of findings suggests that these regions may be involved in learning based on special forms of generalization, but since aversive PIT is a performance phenomenon, these regions are not required.